public class Example4_8 {
    public static void main(String args[]) {
	Circle circle = new Circle();
	circle.setRadius(10);
	Circular circular = new Circular();
	System.out.println("circle的引用:"+circular.bottom);
	System.out.println("圆锥的bottom的引用:"+circular.bottom);
	circular.setHeight(5);
	circular.setBottom(circle);
	System.out.println("circle的引用:"+circle);
	System.out.println("圆锥的bottom的引用:"+circular.bottom);
	System.out.println("圆锥的体积:"+circular.getVolme());
	System.out.println("修改circle的半径，bottom的半径同样变化");
	circle.setRadius(20);
	System.out.println("bottom的半径:"+circular.getBottomRadius());
	System.out.println("重新创建circle,circle的引用将发生变化");
	circle = new Circle();
	System.out.println("circle的引用:"+circle);
	System.out.println("但是不够影响circular的bottom的引用");
	System.out.println("圆锥的bottom的引用:"+circular.bottom);
    }
}

